The popularity of snowboarding has brought awareness to injuries
sustained during the sport. Wrist injuries are among the most common
injuries, and there is an interest in using protective equipment to
prevent these injuries. The purpose of this study was to review the
literature on wrist guard use, injury prevention, the biomechanical
effects of wrist guards, and the various types of wrist guards
commercially available for consumers. A literature search was done using
MEDLINE[R] Ovid (1950 to January 2009), MEDLINE[R] PubMed[R] (1966 to
January 2009), and EMBASE[R] (1980 to January 2009) for studies on
snowboard injuries and wrist guards. References from the studies found
were also reviewed. Two randomized controlled studies (Level I), one
meta-analysis (Level II), eight prospective case control studies (Level
II), one cross-sectional study, and four biomechanical-cadaveric studies
were found from the literature search. Based on the review of this
literature, wrist injuries are among the most common injury type, and
wrist guard use may provide a protective effect in preventing them.
There is no consensus as to what type or design of wrist guard is the
most effective and which wrist guards are available for use by the
consumer.

Snowboarding is one of the fastest growing winter sports, with 2008
statistics showing the number of snowboarders to be 5.9 million,
compared with 6.5 million alpine skiers, in North America. (1) The
rising popularity of extreme sports and high profile snowboard events,
such as the Olympics, X-Games, and the U.S. Open, has helped to catapult
participation of this winter sport. With the increase in popularity, a
number of articles in the recent literature have tackled the topic of
snowboard-related injuries. Various types of studies, including
prospective-retrospective case series, case reports, and case controls
on snowboarding injuries, can now be found in the literature. Many
investigations have found that snowboarders sustain a high number of
upper extremity injuries, especially when compared with skiers. (2-6)
Matsumoto and colleagues (5) found that among injured snowboarders, 40%
sustained upper extremity injuries, while only 19% of skiers did (p <
0.0001). Multiple other studies have found that wrist injuries, in
particular, are prevalent upper extremity injuries. (4,5,7-20) The
population most at risk for this type of injury is beginner
snowboarders. (2,8,21,22) The increased risk of wrist injury can be
attributed to the typical mechanism of a fall when riding a snowboard.
The equipment used in snowboarding consists of the rider strapping in
both feet to a board with bindings that do not release during a fall.
When the rider loses balance, instinctively they fall with their arm
stretched out, putting the participant at increased risk of sustaining
an upper extremity injury.

Protective equipment may play an important role in the prevention
of wrist injuries. Specifically, wrist guard use has been advocated by
authors of multiple papers. (2,13,23,24) Russell and coworkers (25) did
a meta-analysis on this topic, but only evaluated the reduction of wrist
injuries with wrist guard use. The purpose of this study is to review
the literature on wrist guard use, injury prevention, the biomechanical
effects of wrist guards, and the specific design of wrist guards.

Materials and Methods

A literature search was conducted using the computerized literature
databases MEDLINE[R] Ovid (1950 to January 2009), MEDLINE[R] PubMed[R]
(1966 to January 2009), and EMBASE (Excerpta Medica Database) (1980 to
January 2009). Databases were searched using the keywords
"snowboard," "wrist injuries," "upper
extremity," "wrist splint," "wrist brace," and
"wrist guard." References from the articles were also reviewed
for inclusion.

After reviewing all of the articles obtained through the searches,
studies were included if they involved snowboard data collection on
wrist guard use, injuries sustained due to wrist guard use, evaluated
injury prevention-efficacy of wrist guards in snowboarding, cadaveric,
or biomechanical studies on wrist guards.

Results

Sixteen studies were found in the literature search that included
information on wrist guards with the above mentioned inclusion criteria.

Prospective Randomized Controlled Trials (Level I)

Two randomized controlled trials (RCT) were found in the literature
search (Table 1). Machold and associates (24) conducted a study of 721
Austrian students (mean age, 15 years) who snowboarded as part of their
winter sport vacation; 342 participants were randomly assigned to the
protected group, and 379 were assigned to the control, or unprotected,
group. The protected group wore a wrist guard that was designed
specifically for the study; it was palmar in location, curved at the
area of the carpus, the distal end did not exceed the proximal flexion
crease of the hand, and it had an extension of the palmar support to the
forearm. Injuries were classified according to the Abbreviated Injury
Scale (minor: contusion or sprain, or both; moderate: nondisplaced
fracture or epiphysiolysis of radius; severe: displaced fracture). The
incidence of severe wrist injury was 1 of 342 snowboarders (0.0029) in
the protected group and 9 of 379 snowboarders (0.023) in the unprotected
group. There was a decrease in risk by a factor of 0.13 using the wrist
guard (p = 0.05).

Ronning and colleagues (22) studied 5029 snowboarders at the
Hafjell Alpine Center in Norway. They randomized 2515 to the braced
group and 2514 to the control group. The randomly assigned braced group
used a D-ring wrist brace with an aluminum splint on the volar side
(Smith & Nephew, Nesbru, Norway). Both groups were evaluated for an
end point of wrist fracture or sprain; 29 (1.2%) of the unprotected
group sustained wrist injuries, compared with 8 (0.3%) of the protected
group (p = 0.001).

Meta-Analysis (Level II)

One study was found that reviewed the literature to examine the
effectiveness of wrist guards in preventing wrist injuries in
snowboarders (Table 2). Russell and coworkers (25) found six studies
that demonstrated a comparison between wrist guard snowboarders and
unguarded snowboarders and the wrist injuries sustained. They concluded
that based on the literature search, wrist guard use did significantly
reduce the risk of wrist injury. The investigators did note that due to
the various wrist guards that were used in all of the included studies,
no particular wrist guard was deemed optimal to reduce the number of
wrist injuries.

Prospective Case Control Studies (Level III)

Eight prospective case studies were found in the literature search
(Table 3). A case control study was performed in 20 large ski areas in
Quebec, Canada by Hagel and associates. (23) The case group consisted of
1066 persons, who sustained an upper extremity injury. The control group
included 970 injured snowboarders, who sustained injury to a body region
other than the upper extremity. The prevalence of wrist guard use among
snowboarders with upper extremity injuries was 1.6%, compared with 3.9%
in snowboarders with other injuries. There was no mention of the brand
of wrist guards used by participants in the study. Upper extremity
injuries included bruises, dislocations, fractures, and sprains. It was
found that wrist guard use reduced hand-forearm wrist injury by 85% (95%
CI, 0.05-0.45). Injuries to the elbow-shoulder were found to be
increased two-fold, but were not significant (95% CI, 0.70-7.8; p =
0.17).

Upper extremity snowboard injuries were also studied by Idzikowski
and colleagues (13) in Colorado. The study involved 10 seasons
(1998-1998) and included injured snowboarders who sought medical
treatment in 47 medical facilities near Colorado ski resorts. The study
consisted of 7430 snowboard injuries and 3107 non-injured snowboarders
as a control group. The characteristics of the control group were
obtained from the 1995 and 1996 Ski Industries of America Snowboard
Survey and the 1994 Canadian Ski Council National Snowboard Survey; 5.6%
of the injured group wore wrist guards (no specific brands listed). The
control group did not have information related to the use of wrist
guards. Wrist injuries were defined as fractures, dislocations, sprains,
and contusions; 21.6% of all injuries were wrist injuries. Injured
snowboarders without wrist guards were twice as likely to be seen for a
wrist injury as those who wore them (p = 0.0001).

First-day injuries among skiers, snowboarders, and skiboarders in
Scotland were assessed by Langran and Selvaraj. (26) Injured
participants at Cairngorm, Glenshee, and Nevis Range ski areas, during
three winter seasons (1999-2002), who were evaluated by the ski patrol
or those who presented to Aviemore Medical Practice, were included in
the study; some subjects were seen by both. The data included 2124
injuries and 1782 control participants. Demographics and injury
information data were obtained. Control data was collected by
face-to-face interviews on a variety of days and times. In the injured
population, no wrist guards were worn among the first-day participants,
while 1.3% of all injured snowboarders wore them (p = 0.305). There was
no mention of the specific types of wrist guards that were worn.
Injuries sustained by the participants were categorized as fracture,
laceration, sprain, dislocation, subluxation, or bruising. The most
common injury location among snowboarders was the wrist, 33.3% among
first-day participants and 21.2% among all others.

Machold and associates (15) also performed a controlled case study
with a similar population of Austrian students as the prospective
randomized controlled trial (24) mentioned in the previous section. A
total of 2579 snowboarders were included in the study during one
snowboard season 19961997; 152 injured snowboarders were evaluated. A
total of 39% (999 snowboarders) wore wrist guards. There was mention of
multiple gloves, with integrated wrist guards available on the market,
but none were specified in association with injuries. Wrist injuries
were defined as minor (sprains-contusions), moderate (fractures of the
radius), and severe (displaced fractures of the radius); 32.2% of all
injured snowboarders had a lower arm-wrist injury. Lack of use of wrist
guards increased risk of injury by 2.78 (95% CI, 1.05-7.35; p = 0.039).

Made and Elmqvist (16) conducted a 10-year study of snowboard
injuries in Lapland, Sweden, at Tarnaby and Hemavan ski resorts; 568
injured snowboarders were included in the study. An injury form that
included demographics, circumstances surrounding the injury, previous
injuries, and snow conditions was completed by the patients and the
physician. The control group was based on interviews of uninjured
participants on the slopes, and the same form was used to collect data.
Eleven percent of the injured snowboarders wore some kind of wrist guard
(no specific brand mentioned). Wrist guard use was more prevalent in the
advanced group (19%), compared with the intermediate group (10%) and the
beginner group (7%). Injuries were defined as fractures, contusions,
sprains, dislocations, lacerations, and other. Thirty-five percent of
all snowboard injuries involved the lower arm-wrist.

Matsumoto and coworkers (5) conducted a prospective comparative
study of upper extremity injuries sustained between 1995-2000 and
presented to Sumi Memorial Hospital, the only emergency hospital
covering more than 10 skiing facilities; 6837 snowboard injuries were
included in the study, compared to 3 million snowboard participants in
the control group (based on number of passes sold). All injured
participants were asked to fill out a questionnaire, including use of
protective equipment; however, there was no mention about which types of
equipment were used (i.e., wrist guard, helmet, etc.). Among the
participants who had upper extremity injuries, protective equipment was
worn by 13%, as compared to 87% without. The most common location of
snowboard injury was the upper extremity, 40%, compared with 19% in
skiers (p < 0.001). When comparing all the fractures sustained by
snowboarders in the upper extremity, 62% were fractures of the wrist.

O'Neill (27) conducted a prospective control trial in the
White Mountains of New Hampshire. All included participants were
involved in the "Learn to Snowboard" program, where rental
equipment, line ticket, and a 2-hour lesson was part of the package.
This study was conducted during two winter seasons (1998-2000). The
total number of participants was 2355, of which 551 were in the wrist
guard group, and 1804 were in the control group. All participants were
offered a wrist guard (Seneca Sports Inc., Milford, Massachusetts), and
those who refused were put in the control group. Wrist injuries included
sprains (soft tissue swelling in the area of wrist, with pain
significant enough to seek medical attention) and fractures; 2.2% of the
unprotected group sustained wrist injuries, compared with 0% in the
group with wrist guards (p < 0.001).

Slanely and associates (28) did a case control study from Mount
Buller Medical Center, Victoria, Australia, during one snowboard season;
119 injured snowboarders seen at the clinic with a fractured wrist were
included. The control group included the people wearing snowboard boots
in the clinic as patients or as companions. Injured snowboarders with
wrist fractures numbered 119 and the control group 375; 15% of
snowboarders with wrist fractures wore wrist guards, whereas 20% of the
control group wore wrist guards. Use of wrist guards demonstrated a 42%
reduction in wrist fracture but was not statistically significant (OR,
0.58; 95% CI, 0.32-1.04; p = 0.07). No particular wrist guard brand was
mentioned in the study. Twenty-four percent of all the snowboarders
included in the study acquired wrist fractures.

Cross-Sectional Survey

Kroncke and colleagues (29) surveyed the use of protective
equipment among adolescent in-line skaters, skateboarders, and
snowboarders in central southeast Wisconsin, from August 2003 to March
2004. A total of 226 of the 333 surveyed were adolescent snowboarders
(Table 2); 16.7% of the snowboarders stated that they used wrist guards.
Participants were not asked about specific brands of wrist guards used.
Parents were the most common reason for the use of any protective
equipment (35%), while other factors, such as rule-requirement (23%),
friends (20%), sibling (5%), coach (4%), celebrity-advertisement (3%),
and physician (3%) were also mentioned.

Biomechanical and Cadaveric Studies

Four biomechanical studies were found in the literature search
relevant to the evaluation of wrist guards as protective apparel (Table
4). Greenwald and coworkers (30) performed a cadaveric study with wrist
guards. Twelve arms from six fresh-frozen cadavers were used. Each
specimen was mounted to a drop fixture (guillotine-type track), which
was positioned above a force platform (AMTI Corp., Watertown,
Massachusetts). The arms were randomly assigned to a wrist guard
constructed of Kydex[R] (Kleerdex Co. LLC, Mount Laurel, New Jersey),
with a ventral splint from the metacarpophalangeal joint to the
mid-forearm and strapped with three Velcro[R] straps (Velcro[R] USA,
Inc., Manchester, New Hampshire). The specimen was dropped from a 40 cm
height onto the force platform. The braced group had a higher impulse
(change in momentum) applied by the force platform to the drop complex
before failure (p < 0.01). It was noted that the greatest reduction
in momentum was during the first two loading phases in the vertical
force platform. This suggests that the brace was not useful in reducing
momentum after a certain amount of force. The study concluded that the
wrist guard used may have some prophylactic effect in low energy falls,
but not at higher loads.

A biomechanical human subject study was performed by Hwang and
associates. (31) The experiment consisted of 30 young adults; each
subject had two trials, randomized with and without wrist guards. The
wrist guards used in the study were Bone Shieldz (Litchfield, Illinois).
A landing pad with a force transducer was mounted on an inclined wall
(20[degrees] from vertical) in front of the subject. A cable was used to
hold the subject leaning 10[degrees] forward or backward and was
randomly released. The subject stopped the fall with outstretched arms
onto the landing pad, from which impact and braking forces were
measured. It was found that wrist guard use had a significant change in
only the impact force parameters of the backward fall. The investigators
concluded that the wrist guards did not provide statistically
significant reduction of maximum force transmission.

Kim and colleagues (32) designed a biomechanical study with a
mechanical surrogate. The surrogate was the forearm hand complex of an
enhanced airbag interaction (EAI) arm. The surrogate was tested under
five different conditions: 1. bare, 2. UltraWheels wrist guard (First
Team Sports, Inc., Anoka, Minnesota); 3. Sorbothane glove (ER-502,
Ergotech Canada Inc, Ontario, Canada); 4. air cell simple pneumatic
spring mechanism harvested from a pneumatic armband (Aircast Inc.,
Summit, New Jersey); and 5. an "air bladder" (Dielectrics
Industries Inc., Chicopee, Massachusetts). The force was measured with a
six-channel forearm load cell and a commercial force plate (Type
4600-10, Bertec, Columbus, Ohio). The surrogate was mounted on a
guillotine-style platform and was dropped in full extension at four
different heights (13 cm, 25 cm, 38 cm, 51 cm) onto an aluminum block
(ensuring palmar impact) and force plate. It has been reported that the
force for fracture of the radius is 2245 N. The peak impact forces were
smaller in all of the padded conditions, compared with the bare hand
condition (p < 0.05). The air bladder maintained forces below the
peak of 2245 N at all falling heights, while the rest of the protective
devices became ineffective at various heights. The wrist guard became
ineffective at a height of 51 cm. The investigators concluded that wrist
guards may be effective, but may not be protective in all the various
types of impacts in different sporting activities. It was criticized
that common wrist guards are made of rigid splints and do not absorb and
store energy sufficiently. They suggested a wrist guard design with a
pneumatic spring mechanism and more padding to provide more shock
absorption and increase fracture strength.

A cadaveric study was done by Staebler and coworkers (33) to
determine the effect of wrist guards on bone strain. Three pair of
fresh-frozen cadaveric upper extremities were used. Each specimen was
tested unguarded and with two different wrist guards. Guard A was the
Bone Shieldz wrist guard, which had a wraparound design, with the volar
splint elevated off of the wrist. Guard B was the Rollerblades wrist
guard (Minnetonka, Minnesota) with a slip-on design, where the volar
plate was not elevated. A servohydraulic materials testing machine was
used to apply load onto the specimen at the volar pole of the scaphoid
and the load surface (volar angle where the guard would be in contact
with the surface). Strain gauges were attached to the distal radius
(both volar and dorsal), the volar radial shaft, and the dorsal distal
ulna. With wrist guard A, the strain in the dorsal distal radius was 46%
less than with the unguarded specimen, compared with 23% lower with
wrist guard B (p < 0.05). The strain on the volar distal radius was
80% lower with wrist guard A (p < 0.05) versus 30% lower with wrist
guard B (not statistically significant). Only wrist guard A showed a
decreased strain in the dorsal and volar midshaft (61% and 44%
respectively).

Discussion

The growing popularity of snowboarding as a winter sport has
brought attention to the injuries that can be sustained with
participation. All of the studies found in the literature recognize that
wrist injury is one of the most common injuries among snowboarders. The
literature search demonstrated a large number of studies that advocate
the use of wrist guards to prevent lower arm-wrist injuries.

Several studies found that beginners injured their wrists more
often than higher-level snowboarders. This can be explained by the fact
that beginners are more likely to fall, especially during the early part
of their snowboard participation. First-day participants were noted to
have a higher prevalence of wrist injuries when compared with all other
snowboarders. (26) Without proper education on how to fall, beginners
will instinctively fall with their arms outstretched. This mechanism is
classic for distal forearm-wrist injury. As a snowboarder becomes more
advanced in the sport, he or she is less likely to fall as often and
also more likely to attempt, as part of advancing their skills,
acrobatic or aerial maneuvers, or both, that may put them at risk for
other injuries.

Use of protective equipment for the wrist is a method for
prevention of injury. The most compelling evidence is found in the two
randomized control trials that studied the protective effect of wrist
guards. Both demonstrated a statistically significant reduction in wrist
guard injury in the guarded group, compared with the unguarded.

Our search found numerous studies that looked at the effect of
wrist guards; however, there was no consensus on which particular type
of wrist guard would be most effective. The majority of the studies that
we reviewed did not mention a brand name or a description of the type of
wrist guard that was used by participants. Given the wide array of wrist
guards on the market, it is important to know the type and material of a
wrist guard when trying to study the effectiveness of a product.

There were also several studies that looked at the biomechanical
aspect of wrist guards. Each study used a different setup to simulate a
fall and measure the force on the lower arm. Live human subjects,
cadavers, and an EAI arm were used to measure the forces occurring with
falls. The simulation of falls can only be generalized, because it is
very difficult to imitate the environmental factors seen on a snow
covered mountain, and the precise orientation of the forearm-wrist when
a subject falls. There were also various wrist guards-materials used in
all these studies, with no mention of the availability of these products
to the consumer.

The evidence of the protective effects of wrist guards will not be
effective in preventing injuries unless snowboarding participants use
them during sport activity. Many of the studies found low usage of wrist
guards by participants. Some issues to consider are the aesthetics of
the wrist guards, social acceptance, fit of the wrist guard, and
availability.

There is also concern for injuries sustained due to the wrist guard
itself. Cheng and associates did a case report on "splint top"
fractures sustained by rollerbladers wearing wrist guards. All cases had
fractures seen near the proximal border of the wrist splints. There were
no studies found in our literature search about cases with fractures due
to snowboard wrist guards. (34)

Conclusion

This study provided multiple literature findings that support the
high prevalence of wrist injuries in the snowboard population, as well
as the protective effect of wrist guard use. It is important to
understand that these studies did not provide a consensus on the
effectiveness of any one particular wrist guard type. Further research
is required to determine the degree of effectiveness of wrist guards
that are currently available to consumers.

Disclosure Statement

None of the authors have a financial or proprietary interest in the
subject matter or materials discussed, including, but not limited to,
employment, consultancies, stock ownership, honoraria, and paid expert
testimony.

Suezie Kim, M.D., is a Resident in the Department of Orthopaedic
Surgery, and Steve K. Lee, M.D., is Associate Professor of Orthopaedic
Surgery, New York University School of Medicine, and Associate Chief,
Division of Hand Surgery, Department of Orthopaedic Surgery, NYU
Hospital for Joint Diseases, NYU Langone Medical Center, and Co-Chief,
Hand Surgery Service, Bellevue Hospital Center, New York, New York.